I thought I remembered you mentioning your son and grilled chicken and my first memory of the Marketplace was the Subway restaurant right in the front of the place....
If I remember, there were a few other "American" restaurants and fast foods in there. (I was busy checking out the greek, italian and other restaurants.)

Hope whatever you guys wind up doing, that you have a great time.
(we stayed on the ship our first trip and enjoyed the smaller crowds also.)